Method for reducing the bulk and increasing the density of a tissue product

ABSTRACT

A method of increasing the density and reducing the bulk of multi-ply paper products allowing one to reduce the roll size or increase the roll content, while minimizing the destruction of favorable product attributes.

CROSS-REFERENCE TO RELATED APPLICATION

This non-provisional application claims the benefit of priority to U.S.patent application Ser. No. 14/501,982 filed Sep. 30, 2014, now U.S.Pat. No. 9,416,496, which claims the benefit of priority to U.S.Provisional Patent Application No. 61/891,734, filed Oct. 16, 2013,which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention addresses a recent need in the consumer productindustry regarding the increasing size of premium paper goods, e.g.,tissue and towel, and concurrently their packages. As papermakingtechniques have improved and the industry has moved to structured basesheets, the attributes of tissue and towel have improved. Theseimprovements are seen in characteristics like softness, bulk, andabsorbency of the paper, among others. However, concurrent with theseimprovements, the tissue plies have also become thicker making rolls ofpaper, e.g., towels and bathroom tissue, larger. These larger rollsrequire additional space to store and ship. In addition, while the rollproducts have gotten larger, consumer carriers have not. Consumersneither wish to change the size of their bathroom tissue or paper towelholders nor do they want to receive smaller rolls containing less paperproduct. Therefore, a need exists for a paper product that has reducedbulk and increased density that can achieve the consumer's desired sizewithout either requiring reduction of the amount of product orcompromising the properties of the paper product.

SUMMARY OF THE INVENTION

This disclosure provides a method of increasing the density and reducingthe bulk of paper products, thus allowing one to reduce the roll size orincrease the roll content of a product made from that paper, whileminimizing impact on favorable product attributes. Specifically, themethod of this disclosure uses a substantially linear emboss patternwhich decreases the bulk of the product without interfering withimportant consumer characteristics such as strength and absorbency. Thisdisclosure further relates to the paper products having increaseddensity and reduced bulk made by this method. According to oneembodiment, this disclosure provides a method of embossing and plying amulti-ply product.

Products such as paper towels, bathroom tissue, facial tissues, napkins,wipers, and like products, are typically made from one or more webs ofnonwoven paper. For the products to perform as expected by the consumer,the webs from which these products are formed generally exhibitfavorable characteristics of strength, softness, and absorbency.Strength is the ability of a paper web to retain its physical integrityduring use. Softness is the pleasing tactile sensation the consumerperceives as the consumer uses the paper product. Absorbency is thecharacteristic of the paper web which allows it to take up and retainfluids. Typically, the softness and/or absorbency of a paper webincreases at the expense of the strength of the paper web. Consumertesting of products having embossed surfaces show that consumers prefersoft products with relatively high caliper (thickness) and exhibitingaesthetically pleasing decorative patterns. The products of the instantdisclosure achieve all of the consumer's desired attributes while havinga reduced bulk.

Processes for the manufacture of wet-laid paper products generallyinvolve the preparation of an aqueous slurry of cellulosic fibers andsubsequent removal of water from the slurry while rearranging the fibersto form a web. Various types of machinery can be employed to assist inthe dewatering process. A typical manufacturing process employs, forexample, a Fourdrinier wire papermaking machine where a paper slurry isfed onto a surface of a traveling endless wire where the initialdewatering occurs. In a conventional wet press process, the fibers aretransferred directly to a capillary de-watering belt where additionalde-watering occurs. In a structured web process, the fibrous web issubsequently transferred to a papermaking belt where rearrangement anddrying of the fibers is carried out.

As paper production has moved from conventional wet pressing to throughair drying (TAD) and other methods for making structured base sheets,for example, using a perforated polymeric belt as described in U.S. Pat.No. 8,293,072, the tissue base sheets have seen improvements in manysheet characteristics including strength, softness, bulk, andabsorbency. As the caliper of these structured base sheets hasincreased, either package size has increased or the sheet count has beenreduced. A need exists for a reduced bulk premium paper productexhibiting uncompromised quality which would mirror current commercialproducts in size and sheet count. Heretofore, embossing and plying wereroutinely carried out to increase and improve the bulk and absorbency ofa paper product. Embossing is known to increase the bulk of the productto which it is applied. It is therefore surprising that an embossingpattern made up of substantially linear elements can be used to emboss,or emboss and ply, a premium paper product without compromising qualitybut resulting in an end product having a caliper lower than the caliperof the nonwoven web(s) from which it is made.

Additional objects and advantages of the invention will be set forth inpart in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention will be realized and attained bymeans of the elements and combinations particularly pointed out in theappended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed. The accompanyingdrawings, which are incorporated in and constitute a part of thisspecification, illustrate several embodiments of the invention andtogether with the description, serve to explain the principles of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B illustrate an emboss pattern that can be used in themethod according to the invention, and its counterpart non-linear dotrepresentation, respectively.

FIGS. 2A and 2B illustrate an emboss pattern that can be used in themethod according to the invention, and its counterpart non-linear dotrepresentation, respectively.

FIGS. 3A and 3B illustrate an emboss pattern that can be used in themethod according to the invention, and its counterpart non-linear dotrepresentation, respectively.

FIGS. 4A and 4B illustrate an emboss pattern that can be used in themethod according to the invention, and its counterpart non-linear dotrepresentation, respectively.

FIGS. 5A and 5B illustrate an emboss pattern that can be used in themethod according to the invention, and its counterpart non-linear dotrepresentation, respectively.

FIGS. 6A and 6B illustrate an emboss pattern that can be used in themethod according to the invention, and its counterpart non-linear dotrepresentation, respectively.

FIGS. 7A and 7B illustrate an emboss pattern that can be used in themethod according to the invention, and its counterpart non-linear dotrepresentation, respectively.

FIGS. 8A and 8B illustrate an emboss pattern that can be used in themethod according to the invention, and its counterpart non-linear dotrepresentation, respectively.

FIG. 9 illustrates an emboss pattern that can be used in the methodaccording to the invention.

FIGS. 10 to 22 are graphical representations based upon the datapresented in Example 2.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the terms “paper web,” “web,” “paper sheet,” “fibrousstructure,” “nonwoven web,” and “paper product” are all usedinterchangeably to refer to sheets of paper products suitable forconsumer use in, for example, paper toweling, bath tissue, napkins,facial tissue, wipers and the like. Products of the disclosure can beany paper product in which the bulk and density of the product wouldbenefit from reduction and in which it is important that softness,absorbency and strength not be substantially negatively affected.Products contemplated for production using the disclosed embossingmethod can be in the areas of tissue and towel, feminine hygiene, adultincontinence and baby products, including, for example, baby wipes ordiapers. The paper products as described can be in the form of, forexample, stacks or rolls. In one embodiment, the paper products asdescribed may be wound with or without a core to form a rolled paperproduct. Rolled products may comprise a plurality of connected andperforated sheets that are separable and dispensable from adjacentsheets.

The paper of the present invention may comprise papermaking fibers ofboth hardwoods and softwoods pulps. “Hardwood pulps” as used hereinrefers to fibrous pulp derived from the woody substance of deciduoustrees (angiosperms). “Softwood pulps” are fibrous pulps derived from thewoody substance of coniferous trees (gymnosperms). Blends of hardwoodand softwood are also suitable to produce the paper products asdescribed. In one embodiment the plies of the paper product may beheterogeneous web layers. In another embodiment, the plies may benon-heterogeneous or stratified. Also applicable to the presentinvention are fibers derived from recycled paper, which may contain anyor all of the above categories of fibers. According to yet anotherembodiment, the fibers may include one or more non-wood based fiber.Wood pulps useful herein include chemical pulps such as, sulfite andsulfate (sometimes called Kraft) pulps as well as mechanical pulpsincluding for example, ground wood, ThermoMechanical Pulp (TMP) andChemi-ThermoMechanical Pulp (CTMP).

Paper products of the present disclosure may be produced according toany art recognized wet laid or air laid method. According to oneembodiment, the paper product as described is made from one or more basesheet(s) chosen from conventional wet press (CWP) base sheet(s),structured base sheet(s) including both TAD and e-TAD, air laid basesheet(s) and combinations thereof.

Any art recognized process for making the base sheet(s) is suitable foruse in the present invention. Typically, depending upon the desired enduse, paper products are generally comprised of papermaking fibers andsmall amounts of chemical functional agents such as wet strength or drystrength agents, binders, retention aids, surfactants, size, chemicalsofteners, and release agents. Additionally, filler materials may alsobe incorporated into the web. All such base sheets may be used in themethod described in the instant disclosure.

The paper product of the present invention may exhibit a basis weight offrom about 20 g/m² to about 120 g/m², for example, from about 30 g/m² toabout 65 g/m², for example, from about 37 g/m² to about 50 g/m².

Paper products as described are embossed. “Embossed” as used herein withrespect to a fibrous web means a fibrous web that has been subjected toa process which converts a smooth surfaced fibrous web to a decorativesurface by replicating a design on one or more emboss rolls, which forma nip through which the fibrous web passes. Embossed does not includecreping, microcreping, printing or other processes that may impart atexture and/or decorative pattern to a fibrous structure.

During a typical embossing process, a web is fed through a nip formedbetween juxtaposed generally axially parallel rolls. Embossing elementson the rolls compress and/or deform the web. If a multi-ply product isbeing formed, two or more webs, i.e., plies, are fed through the nip andregions of each ply are brought into a contacting relationship with theopposing ply. The embossed regions of the plies produce an aestheticpattern and may provide a means for joining and maintaining the plies inface-to-face contacting relationship.

Generally, the embossing apparatus will include one or more rolls havingprotuberances and/or depressions formed therein. A corresponding backuproll presses the web against the embossing roll such that the embossedpattern is imparted to the web as it passes between the nip formedbetween the embossing roll and the backup roll. Any art recognizedembossing configuration can be used in the method of the presentdisclosure.

While fiber-to-steel, steel-to-steel or rubber-to-rubber embossingoperations can be used, the most common embossing configuration isrubber-to-steel. In rubber-to-steel embossing, the steel embossing rollis provided with protuberances and/or depressions and the web is pressedagainst the embossing roll by a rubber backing roll as the web passesthrough the nip formed between the rubber and the steel rolls. Therubber backing roll accommodates the protuberances and/or depressions byvirtue of its resilience and the rubber flows about the protuberancesand/or depressions as force is applied to urge the rolls together. Analternative rubber-to-steel configuration is a mated configuration. Thisconfiguration mates a steel embossing roll having a plurality ofprotuberances extending therefrom with a patterned rubber backing rollwhich urges the fibrous web substrate against the embossing roll therebyimparting a highly defined embossed pattern to the paper substrate forforming paper towels, napkins or tissues. As the paper substrate passesthrough the nip between the rolls, the web is forced about theprotuberances and against the land areas of the steel roll, as well asinto the indentations and outer peripheral surfaces of the rubber roll.As a result, a highly defined embossed pattern is provided. According toone embodiment of the invention, the embossing operation is a rubber tosteel configuration.

The paper products as disclosed bear an emboss pattern that compriseslinear embossments. A linear embossment is characterized by having atotal embossment length to total embossment width (or an aspect ratio)of at least about 5. Smaller, embossments having an aspect ratio of lessthan 5 are referred to herein as dot embossments; however they can takeany shape. According to one embodiment, linear embossments make up atleast about 80% of the embossments on the paper product, for example, atleast about 90%, for example at least about 95%. According to oneembodiment, the emboss pattern is made up solely (100%) of linear embosselements.

According to one embodiment, the linear emboss elements have an aspectratio of at least about 5, for example, at least about 10, for example,at least about 20, for example, at least about 30, for example, at leastabout 40, for example, at least about 50.

According to another embodiment, the depth of embossments are from about1.25 to about 3.5 times the caliper of the unembossed base sheet(s), forexample, about 1.5 to about 2.5 times, for example, from about 1.5 toabout 2.0. In the embodiment where two plies are used, this issufficient to maintain good ply lamination with a consumer preferredappearance while reducing the finished product caliper to something lessthan the expected caliper of the two unembossed plies combined. Thisallows for the production of high performance structured base sheetproducts with a higher finished product density. Embossing depths foruse in the present invention are generally at least about 30 mils (762μm), for example, at least about 35 mils (889 μm), for example, at leastabout 40 mils (1016 μm) at least about 45 mils (1143 μm), for example,at least about 50 mils (1270 μm). As described herein embossing depthcorresponds to the height of the majority elements on the emboss roll.

Without wishing to be bound by theory, we believe the linear elements,coupled with the defined depth of embossment provide more surface area,which minimizes the impact on sheet properties while resulting in anaesthetically pleasing product that can be packaged in the desired size,e.g., wound to the desired roll size, without giving up sheet count.

According to one embodiment, the embossments cover greater than about22%, for example, from about 22 to about 50%, for example, from about 25to about 50%, for example about 22 to about 30% of the total area of thefinished product.

A multitude of combinations of emboss coverage, emboss depth, embossaspect ratio and percent linear embosses would be apparent to theskilled artisan. The combinations set forth below are merely exemplary.

According to one embodiment, the paper products bearing the linearemboss pattern exhibit at least about 1% less caliper than the basesheet(s), for example, at least about 1.5% less caliper, for example, atleast about 2% less caliper, for example, at least about 2.5% lesscaliper, for example, at least about 3% less caliper, for example atleast about 3.5% less caliper, for example, at least about 4% lesscaliper, for example, at least about 4.5%, for example, at least about5% less caliper.

TABLE 1 Emboss Aspect Ratio of linear embossments and percentage oflinear Percent of overall Emboss Coverage embossments at that patternthat is made up (%) Emboss Depth (mils) Aspect ratio of linearembossments 22 to 50 At least 35 At least 5-100% At least 80 22 to 50 Atleast 40 At least 5-100% At least 80 22 to 50 At least 45 At least5-100% At least 80 22 to 50 At least 55 At least 5-100% At least 80 22to 50 At least 35 At least 5-100% At least 90 22 to 50 At least 40 Atleast 5-100% At least 90 22 to 50 At least 45 At least 5-100% At least90 22 to 50 At least 55 At least 5-100% At least 90 22 to 50 At least 35At least 5-100% 100 22 to 50 At least 40 At least 5-100% 100 22 to 50 Atleast 45 At least 5-100% 100 22 to 50 At least 55 At least 5-100% 100 22to 50 At least 35 At least 10-100% At least 80 22 to 50 At least 40 Atleast 10-100% At least 80 22 to 50 At least 45 At least 10-100% At least80 22 to 50 At least 55 At least 10-100% At least 80 22 to 50 At least35 At least 10-100% At least 90 22 to 50 At least 40 At least 10-100% Atleast 90 22 to 50 At least 45 At least 10-100% At least 90 22 to 50 Atleast 55 At least 10-100% At least 90 22 to 50 At least 35 At least10-100% 100 22 to 50 At least 40 At least 10-100% 100 22 to 50 At least45 At least 10-100% 100 22 to 50 At least 55 At least 10-100% 100 22 to50 At least 35 At least 20-100% At least 80 22 to 50 At least 40 Atleast 20-100% At least 80 22 to 50 At least 45 At least 20-100% At least80 22 to 50 At least 55 At least 20-100% At least 80 22 to 50 At least35 At least 20-at least At least 80 80% 22 to 50 At least 40 At least20-at least At least 80 80% 22 to 50 At least 45 At least 20-at least Atleast 80 80% 22 to 50 At least 55 At least 20-at least At least 80 80%22 to 50 At least 35 At least 30-at least At least 80 50% 22 to 50 Atleast 40 At least 30-at least At least 80 50% 22 to 50 At least 45 Atleast 30-at least At least 80 50% 22 to 50 At least 55 At least 30-atleast At least 80 50% 22 to 50 At least 35 At least 30-at least At least90 50% 22 to 50 At least 40 At least 30-at least At least 90 50% 22 to50 At least 45 At least 30-at least At least 90 50% 22 to 50 At least 55At least 30-at least At least 90 50% 22 to 50 At least 35 At least 20-atleast At least 95 80% 22 to 50 At least 40 At least 20-at least At least95 80% 22 to 50 At least 45 At least 20-at least At least 95 80% 22 to50 At least 55 At least 20-at least At least 95 80% 22 to 50 At least 35At least 40-at least At least 80 50% 22 to 50 At least 40 At least 40-atleast At least 80 50% 22 to 50 At least 45 At least 40-at least At least80 50% 22 to 50 At least 55 At least 40-at least At least 80 50% 22 to50 At least 35 At least 40-at least At least 90 50% 22 to 50 At least 40At least 40-at least At least 90 50% 22 to 50 At least 45 At least 40-atleast At least 90 50% 22 to 50 At least 55 At least 40-at least At least90 50% 22 to 50 At least 35 At least 20-at least 100 50% 22 to 50 Atleast 40 At least 20-at least 100 50% 22 to 50 At least 45 At least20-at least 100 50% 22 to 50 At least 55 At least 20-at least 100 50% 22to 50 At least 35 At least 30-at least 100 50% 22 to 50 At least 40 Atleast 30-at least 100 50% 22 to 50 At least 45 At least 30-at least 10050% 22 to 50 At least 55 At least 30-at least 100 50% 22 to 50 At least35 At least 40-at least 100 50% 22 to 50 At least 40 At least 40-atleast 100 50% 22 to 50 At least 45 At least 40-at least 100 50% 22 to 50At least 55 At least 40-at least 100 50% 22 to 30 At least 35 At least10-at least 100 50% 22 to 30 At least 40 At least 10-at least 100 50% 22to 30 At least 45 At least 10-at least 100 50% 22 to 30 At least 55 Atleast 10-at least 100 50% 22 to 30 At least 35 At least 20-at least 10050% 22 to 30 At least 40 At least 20-at least 100 50% 22 to 30 At least45 At least 20-at least 100 50% 22 to 30 At least 55 At least 20-atleast 100 50% 22 to 30 At least 35 At least 30-at least 100 50% 22 to 30At least 40 At least 30-at least 100 50% 22 to 30 At least 45 At least30-at least 100 50% 22 to 30 At least 55 At least 30-at least 100 50% 22to 30 At least 35 At least 40-at least 100 50% 22 to 30 At least 40 Atleast 40-at least 100 50% 22 to 30 At least 45 At least 40-at least 10050% 22 to 30 At least 55 At least 40-at least 100 50%

As seen from table above, the emboss configuration may vary. So,according to the first embodiment set forth in the table above, thepaper product would have 22 to 50% of its surface covered withembossments that are at least 35 mils high and where linear embossmentsmake up at least 80% of the total embossments and 100% of the linearembossments have an aspect ratio of at least 5. And, according to thelast embodiment set forth in the table above, the paper product wouldhave 22 to 30% of its surface covered with embossments that are at least55 mils high and where linear embossments make up 100% of the totalembossments and at least 50% of the linear embossments have an aspectratio of at least 40.

According to one embodiment, the paper products bearing the linearemboss pattern exhibit at least about 5% less caliper than the samepattern formed from dots (See, FIG. 1A versus FIG. 1B). According toanother embodiment the paper products bearing the linear emboss patternexhibit at least about 6% less caliper than the same pattern formed fromdots, for example, at least about 8% less caliper, for example at least,about 10% less caliper, for example, at least about 12% less caliper.

FIG. 1A illustrates one pattern that may be used in the method of thepresent disclosure to reduce the bulk of the paper product. This patternis made up of linear segments that are curved and flow around each otherin a swirling pattern. FIG. 1B illustrates the pattern of FIG. 1A as itwould be represented by dot embossments. FIGS. 2A, 3A, 4A. 5A, 6A, 7Aand 8A illustrate other patterns that may be used in the method of thepresent disclosure to reduce the bulk of the paper product. FIGS. 2B,3B, 4B 5B 6B, 7B and 8B illustrates the same patterns of FIGS. 2A, 3A,4A, 5A, 6A, 7A and 8A, respectively, as they would be represented by dotembossments. FIG. 9 illustrates a pattern for use in the instantinvention where the pattern is made up of linear segments of differingsizes.

As used herein, “about” is meant to account for variations due toexperimental error. All measurements are understood to be modified bythe word “about”, whether or not “about” is explicitly recited, unlessspecifically stated otherwise. Thus, for example, the statement “anemboss depth of at least 30 mils” is understood to mean “an emboss depthof at least about 30 mils.”

The details of one or more non-limiting embodiments of the invention areset forth in the examples below. Other embodiments of the inventionshould be apparent to those of ordinary skill in the art afterconsideration of the present disclosure.

EXAMPLES

The product characteristics measured in the Examples, infra, weremeasured according the following methodologies. Throughout thisspecification and claims, it is to be understood that, unless otherwisespecified, physical properties are measured after the web has beenconditioned according to Technical Association of the Pulp and PaperIndustry (TAPPI) standards. If no test method is explicitly set forthfor measurement of any quantity mentioned herein, it is to be understoodthat TAPPI standards should be applied.

Basis Weight

Unless otherwise specified, “basis weight”, BWT, bwt, BW, and so forth,refers to the weight of a 3000 square-foot ream of product (basis weightis also expressed in g/m² or gsm). Likewise, “ream” means a 3000square-foot ream, unless otherwise specified. Likewise, percent or liketerminology refers to weight percent on a dry basis, that is to say,with no free water present, which is equivalent to 5% moisture in thefiber.

Caliper

Calipers and/or bulk reported herein may be measured at 8 or 16 sheetcalipers as specified. The sheets are stacked and the calipermeasurement taken about the central portion of the stack. Preferably,the test samples are conditioned in an atmosphere of 23°±1.0° C.(73.4°±1.8° F.) at 50% relative humidity for at least about 2 hours andthen measured with a Thwing-Albert Model 89-II-JR or Progage ElectronicThickness Tester with 2-in diameter anvils, 539±10 grams dead weightload, and 0.231 in/sec descent rate. For finished product testing, eachsheet of product to be tested must have the same number of plies as theproduct as sold. For testing in general, eight sheets are selected andstacked together. For napkin testing, napkins are unfolded prior tostacking. For base sheet testing off of winders, each sheet to be testedmust have the same number of plies as produced off of the winder. Forbase sheet testing off of the papermachine reel, single plies must beused. Sheets are stacked together aligned in the machine direction (MD).Bulk may also be expressed in units of volume/weight by dividing caliperby basis weight.

MD and CD Tensile, Stretch, Break Modulus and TEA

Dry tensile strengths (MD and CD), stretch, ratios thereof, modulus,break modulus, stress and strain are measured with a standard Instrontest device or other suitable elongation tensile tester, which may beconfigured in various ways, typically, using 3 inch or 1 inch widestrips of tissue or towel, conditioned in an atmosphere of 23°±1° C.(73.4°±1° F.) at 50% relative humidity for 2 hours. The tensile test isrun at a crosshead speed of 2 in/min. Break modulus is expressed ingrams/3 inches/% strain or its SI equivalent of g/mm/% strain. % strainis dimensionless and need not be specified. Unless otherwise indicated,values are break values. GM refers to the square root of the product ofthe MD and CD values for a particular product. Tensile energy absorption(TEA), which is defined as the area under the load/elongation(stress/strain) curve, is also measured during the procedure formeasuring tensile strength. Tensile energy absorption is related to theperceived strength of the product in use. Products having a higher TEAmay be perceived by users as being stronger than similar products thathave lower TEA values, even if the actual tensile strength of the twoproducts are the same. In fact, having a higher tensile energyabsorption may allow a product to be perceived as being stronger thanone with a lower TEA, even if the tensile strength of the high-TEAproduct is less than that of the product having the lower TEA. When theterm “normalized” is used in connection with a tensile strength, itsimply refers to the appropriate tensile strength from which the effectof basis weight has been removed by dividing that tensile strength bythe basis weight. In many cases, similar information is provided by theterm “breaking length”.

GMT refers to the geometric mean tensile strength of the CD and MDtensile. Tensile energy absorption (TEA) is measured in accordance withTAPPI test method T494 om-01.

Tensile ratios are simply ratios of an MD value determined by way of theforegoing methods divided by the corresponding CD value. Unlessotherwise specified, a tensile property is a dry sheet property.

Perforation Tensile

The perforation tensile strength (force per unit width required to breaka specimen) is measured generally using a constant rate of elongationtensile tester equipped with 3-in wide jaw line contact grips.Typically, the test is carried out using 3 inch wide by 5 inch longstrips of tissue or towel, conditioned in an atmosphere of 23°±1.0° C.(73.4°±1.8° F.) at 50% relative humidity for 2 hours. The crossheadspeed of the tensile tester is generally set to 2.0 in. per minute. Thejaw span is 3 inches. The specimen is clamped into the upper grip andallowed to hang freely. The lower grip is then used to grip the free endof the specimen tightly enough to hold the sample, but not withsufficient pressure to damage the sample. The sample is stretched untilit breaks and the perforation tensile is recorded.

Wet Tensile

The wet tensile of the tissue of the present invention is measuredgenerally following TAPPI Method T 576 pm 7, using a three-inch (76.2mm) wide strip of tissue that is folded into a loop, clamped in aspecial fixture termed a Finch Cup, then immersed in water. A suitableFinch cup, 3-in., with base to fit a 3-in. grip, is available from:

High-Tech Manufacturing Services, Inc.

-   -   3105-B NE 65^(th) Street    -   Vancouver, Wash. 98663    -   360-696-1611    -   360-696-9887 (FAX).

For fresh basesheet and finished product (aged 30 days or less for towelproduct, aged 24 hours or less for tissue product) containing wetstrength additive, the test specimens are placed in a forced air ovenheated to 105° C. (221° F.) for five minutes. No oven aging is neededfor other samples. The Finch cup is mounted onto a tensile testerequipped with a 2.0 pound load cell with the flange of the Finch cupclamped by the tester's lower jaw and the ends of tissue loop clampedinto the upper jaw of the tensile tester. The sample is immersed inwater that has been adjusted to a pH of 7.0±0.1 and the tensile istested after a 5 second immersion time using a crosshead speed of 2inches/minute. The results are expressed in g/3 in., dividing thereadout by two to account for the loop as appropriate.

Roll Compression

Roll compression is measured by compressing a roll under a 1500 g flatplaten of a test apparatus. Sample rolls are conditioned and tested inan atmosphere of 23.0°±1.0° C. (73.4°±1.8° F.). A suitable testapparatus with a movable 1500 g platen (referred to as a height gauge)is available from:

Research Dimensions

1720 Oakridge Road

Neenah, Wis. 54956

-   -   920-722-2289    -   920-725-6874 (FAX).

The test procedure is generally as follows:

-   -   (a) Raise the platen and position the roll to be tested on its        side, centered under the platen, with the tail seal to the front        of the gauge and the core parallel to the back of the gauge.    -   (b) Slowly lower the platen until it rests on the roll.    -   (c) Read the compressed roll diameter or sleeve height from the        gauge pointer to the nearest 0.01 inch (0.254 mm).    -   (d) Raise the platen and remove the roll.    -   (e) Repeat for each roll or sleeve to be tested.

To calculate roll compression (RC) in percent, the following formula isused:

${R\; C\mspace{11mu}(\%)} = {100 \times \frac{\left( {{{initial}\mspace{14mu}{roll}\mspace{14mu}{diameter}} - {{compressed}\mspace{14mu}{roll}\mspace{14mu}{diameter}}} \right)}{{initial}\mspace{14mu}{roll}\mspace{14mu}{diameter}}}$SAT Capacity

Absorbency of the inventive products is measured with a simpleabsorbency tester. The simple absorbency tester is a particularly usefulapparatus for measuring the hydrophilicity and absorbency properties ofa sample of tissue, napkins, or towel. In this test, a sample of tissue,napkins, or towel 2.0 inches in diameter is mounted between a top flatplastic cover and a bottom grooved sample plate. The tissue, napkin, ortowel sample disc is held in place by a ⅛ inch wide circumference flangearea. The sample is not compressed by the holder. De-ionized water at73° F. is introduced to the sample at the center of the bottom sampleplate through a 1 mm. diameter conduit. This water is at a hydrostatichead of minus 5 mm. Flow is initiated by a pulse introduced at the startof the measurement by the instrument mechanism. Water is thus imbibed bythe tissue, napkin, or towel sample from this central entrance pointradially outward by capillary action. When the rate of water imbibitiondecreases below 0.005 gm water per 5 seconds, the test is terminated.The amount of water removed from the reservoir and absorbed by thesample is weighed and reported as grams of water per square meter ofsample or grams of water per gram of sheet. In practice, an M/K SystemsInc. Gravimetric Absorbency Testing System is used. This is a commercialsystem obtainable from M/K Systems Inc., 12 Garden Street, Danvers,Mass., 01923. WAC, or water absorbent capacity, also referred to as SAT,is actually determined by the instrument itself. WAC is defined as thepoint where the weight versus time graph has a “zero” slope, i.e., thesample has stopped absorbing. The termination criteria for a test areexpressed in maximum change in water weight absorbed over a fixed timeperiod. This is basically an estimate of zero slope on the weight versustime graph. The program uses a change of 0.005 g over a 5 second timeinterval as termination criteria; unless “Slow SAT” is specified inwhich case the cut off criteria is 1 mg in 20 seconds.

Water absorbency rate is measured in seconds and is the time it takesfor a sample to absorb a 0.1 gram droplet of water disposed on itssurface by way of an automated syringe. The test specimens arepreferably conditioned at 23° C.±1.0° C. (73.4° F.±1.8° F.) at 50%relative humidity. For each sample, 4 3×3 inch test specimens areprepared. Each specimen is placed in a sample holder such that a highintensity lamp is directed toward the specimen. 0.1 ml of water isdeposited on the specimen surface and a stop watch is started. When thewater is absorbed, as indicated by lack of further reflection of lightfrom the drop, the stopwatch is stopped and the time recorded to thenearest 0.1 seconds. The procedure is repeated for each specimen and theresults averaged for the sample. SAT Rate is determined by graphing theweight of water absorbed by the sample (in grams) against the squareroot of time (in seconds). The SAT rate is the best fit slope between 10and 60 percent of the end point (grams of water absorbed).

Sensory Softness

Sensory softness of the samples was determined by using a panel oftrained human subjects in a test area conditioned to TAPPI standards(temperature of 71.2° F. to 74.8° F., relative humidity of 48% to 52%).The softness evaluation relied on a series of physical references withpredetermined softness values that were always available to each trainedsubject as they conducted the testing. The trained subjects directlycompared test samples to the physical references to determine thesoftness level of the test samples. The trained subjects assigned anumber to a particular paper product, with a higher sensory softnessnumber indicating a higher the perceived softness.

Example 1

Paper towel base sheets were produced in a consistent manner and wereeither unembossed or embossed with either the current Brawny® non-linearembossing pattern of FIG. 5B or a linear pattern according to thepresent invention, i.e., the pattern of FIG. 5A and variations thereof.The characteristics for the unembossed base sheets and the two plyproduct are set forth in Table 2, below.

Table 3 sets forth the product characteristics for an embossed papertowel product bearing the current commercial, non-linear embossingpattern, both at a commercial emboss depth and at a depth of 45 mils. InColumn 3 of Table 3 a comparison is made between the 45 mils embossedproduct and the unembossed base sheet described in Table 2. As can beseen from Table 3, column 3, the caliper of the product increased withembossing by 6.22%. The Wet Tensile strength remained largelyunaffected.

Table 4 sets forth finished product characteristics for four paper towelproducts embossed with linear patterns according to the instant method.Table 5 compares those embossed product characteristics to theunembossed base sheet of Table 2. As can be seen in Table 5, when apaper towel was embossed with a substantially linear pattern asdescribed herein, the caliper of the two ply product was less than thecaliper of the two base sheets. As can also be seen from Table 5, theimpact on sheet strength was minimal, if negative. In two instances, theCD wet tensile increased. Finally, while the absorbency of the finalproduct did go down, the change in absorbency as reflected by the SATcapacity was always less than 10% and in some instances less than 5%.Accordingly, in this embodiment, an embossed paper product resultshaving a lower caliper and higher density than the original base sheetsand a significantly lower caliper than paper products embossed with atraditional non-linear pattern. In addition, the lower caliper andhigher density do not result in changes in strength or sensory softnessand only exhibit minor losses in absorbency.

TABLE 2 Combined Base Description Ply 1 Ply 2 Sheet Basis Weight lb/3000ft² 13.55 13.45 27.00 Caliper 8 Sheetmils/8 89.2 92.7 181.9 sht TensileMD g/3 in 1385.18 1569.31 2954.49 Stretch MD % 15.48 16.76 16.12 TensileCD g/3 in. 1465.36 1478.55 2943.92 Stretch CD % 8.76 9.30 9.03 TensileGM g/3 in. 1424.06 1522.78 2946.84 Tensile Dry Ratio 0.95 1.06 1.00Unitless Perf Tensile g/3 in. Wet Tens Finch 424.63 415.16 839.78 CuredCD g/3 in. Tensile Wet/Dry CD 0.29 0.28 0.29 Unitless SAT Capacity g/m²SAT Rate g/s^(0.5) SAT Times Break Modulus MD 88.16 92.48 180.64 gms/%Break Modulus CD 169.89 158.09 327.98 gms/% Break Modulus GM 122.38120.91 243.29 gms/% Modulus MD g/% Stretch Modulus CD g/% StretchModulus GM g/% Stretch TEA MD mm-g/mm² 1.37 1.62 2.99 TEA CD mm-g/mm²0.81 0.88 1.69 Roll Diameter In. Roll Compression Value % RollCompression in. Basis Weight Raw 1.02 1.02 2.04 Wtg. Sensory Softness5.4

TABLE 3 Current Product at a Change from penetration of 45 Basesheetbased on Description Current Product mils 45 mils penetration BasisWeight lb/3000 ft² 26.57 26.29 −2.63 Caliper 8 Sheetmils/8 195.05 193.226.22 sht Tensile MD g/3 in 3083.12 3128.73 5.90 Stretch MD % 16.68 16.572.80 Tensile CD g/3 in. 2837.73 2903.75 −1.36 Stretch CD % 10.03 10.0411.18 Tensile GM g/3 in. 2957.68 3013.46 2.26 Tensile Dry Ratio 1.091.08 7.86 Unitless Perf Tensile g/3 in. 732.25 725.78 Wet Tens Finch813.27 840.26 0.06 Cured CD g/3 in. Tensile Wet/Dry CD 0.29 0.29 −0.15Unitless SAT Capacity g/m² 512.24 521.83 −1.72 SAT Rate g/s^(0.5) 0.260.31 SAT Times 42.03 35.31 Break Modulus MD 184.92 188.78 4.51 gms/%Break Modulus CD 282.17 286.38 −12.69 gms/% Break Modulus GM 228.39232.47 −4.45 gms/% Modulus MD g/% 41.55 42.65 Stretch Modulus CD g/%65.35 67.85 Stretch Modulus GM g/% 52.08 53.78 Stretch TEA MD mm-g/mm²3.13 3.17 6.10 TEA CD mm-g/mm² 1.84 1.89 11.64 Roll Diameter In. 6.075.64 Roll Compression 3.51 3.72 Value % Roll Compression in. 5.86 5.43Basis Weight Raw 2.01 1.99 −2.63 Wtg. Sensory Softness 5.60 5.7

TABLE 4 Invention at Penetration of 45 mils Description Pattern APattern B Pattern C Pattern D Basis Weight 26.07 26.47 26.61 26.36lb/3000 ft² Caliper 8 178.46 180.60 179.05 175.09 Sheetmils/8 shtTensile MD g/3 in 3000.08 3337.16 3086.51 3161.29 Stretch MD % 15.5516.07 15.83 15.38 Tensile CD g/3 in. 2867.19 3185.83 2954.76 2911.81Stretch CD % 9.55 9.66 9.46 9.44 Tensile GM g/3 in. 2931.82 3260.203019.6 3033.45 Tensile Dry Ratio 1.05 1.05 1.04 1.09 Unitless PerfTensile g/3 in. 706.15 727.19 709.54 604.07 Wet Tens Finch 822.45 844.51856.00 809.51 Cured CD g/3 in. Tensile Wet/Dry 0.29 0.27 0.29 0.28 CDUnitless SAT Capacity g/m² 498.4 491.19 493.76 487.84 SAT Rate g/s^(0.5)0.25 0.24 0.27 0.26 SAT Times 35.62 32.22 29.41 28.87 Break Modulus MD194.47 205.36 195.14 205.07 gms/% Break Modulus CD 296.92 332.89 316.78307.04 gms/% Break Modulus GM 240.26 261.45 248.60 250.88 gms/% ModulusMD g/% 45.80 50.38 45.43 49.37 Stretch Modulus CD g/% 67.96 77.77 71.2767.81 Stretch Modulus GM g/% 55.76 62.59 56.89 57.82 Stretch TEA MD mm-2.90 3.44 3.08 3.02 g/mm² TEA CD mm- 1.79 2.01 1.78 1.71 g/mm² RollDiameter In. 5.86 5.76 5.78 5.65 Roll Compression 4.21 5.27 5.48 4.96Value % Roll Compression 5.61 5.45 5.46 5.37 in. Basis Weight Raw 1.972.00 2.01 1.99 Wtg. Sensory Softness 5.30 5.40 5.70 5.50

TABLE 5 Invention at Penetration of 45 mils (Percent Change fromBasesheet) Description Pattern A Pattern B Pattern C Pattern D BasisWeight −3.45 1.94 1.45 2.36 lb/3000 ft² Caliper 8 −1.89 0.71 1.57 3.74Sheetmils/8 sht Tensile MD g/3 in 1.54 −12.95 −4.47 −7.00 Stretch MD %−3.52 0.31 1.81 4.61 Tensile CD g/3 in. −2.61 −8.22 −0.37 1.09 StretchCD % 5.78 −7.01 −4.74 −4.55 Tensile GM g/3 in. −0.51 −10.63 −2.47 −2.94Tensile Dry Ratio 4.71 −4.41 −4.88 −8.22 Unitless Perf Tensile g/3 in.Wet Tens Finch −2.06 −0.56 −1.93 3.61 Cured CD g/3 in. Tensile Wet/Dry1.09 7.06 −1.57 2.50 CD Unitless SAT Capacity g/m² −6.13 −7.49 −7.01−8.12 SAT Rate g/s^(0.5) SAT Times Break Modulus MD 7.66 −13.69 −8.03−13.53 gms/% Break Modulus CD −9.47 −1.49 3.41 6.39 gms/% Break ModulusGM −1.25 −7.46 −2.18 −3.12 gms/% Modulus MD g/% Stretch Modulus CD g/%Stretch Modulus GM g/% Stretch TEA MD mm- −2.77 −15.32 −3.00 −1.18 g/mm²TEA CD mm- 5.91 −18.95 −5.50 −1.49 g/mm² Roll Diameter In. RollCompression Value % Roll Compression in. Basis Weight Raw −3.45 1.941.45 2.36 Wtg. Sensory Softness

Example 2

Example 2 was carried out in the same manner as Example 1, using anemboss penetration of 55 mils. Results are set forth in Tables 6-8,below.

TABLE 6 Current Product at a Change from penetration of 55 Basesheetbased on Description Current Product mils 55 mils penetration BasisWeight lb/3000 ft² 26.57 26.36 −2.38 Caliper 8 Sheetmils/8 195.05 206.2313.37 sht Tensile MD g/3 in 3083.12 2865.60 −3.01 Stretch MD % 16.6816.84 4.49 Tensile CD g/3 in. 2837.73 2611.43 −11.29 Stretch CD % 10.0310.22 13.18 Tensile GM g/3 in. 2957.68 2735.26 −7.18 Tensile Dry Ratio1.09 1.10 9.77 Unitless Perf Tensile g/3 in. 732.25 667.89 Wet TensFinch 813.27 744.95 −11.29 Cured CD g/3 in. Tensile Wet/Dry CD 0.29 0.29−1.64 Unitless SAT Capacity g/m² 512.24 523.31 −1.72 SAT Rate g/s^(0.5)0.26 0.33 SAT Times 42.03 40.09 Break Modulus MD 184.92 170.36 −5.69gms/% Break Modulus CD 282.17 253.72 −22.64 gms/% Break Modulus GM228.39 207.88 −14.55 gms/% Modulus MD g/% 41.55 37.07 Stretch Modulus CDg/% 65.35 57.73 Stretch Modulus GM g/% 52.08 46.24 Stretch TEA MDmm-g/mm² 3.13 2.91 −2.58 TEA CD mm-g/mm² 1.84 1.74 3.29 Roll DiameterIn. 6.07 5.90 Roll Compression 3.51 4.80 Value % Roll Compression in.5.86 5.62 Basis Weight Raw 2.01 1.99 −2.38 Wtg. Sensory Softness 5.606.1

TABLE 7 Invention at Penetration of 55 mils Description Pattern APattern B Pattern C Pattern D Basis Weight 26.12 26.19 26.40 26.18lb/3000 ft² Caliper 8 183.32 192.26 187.54 187.61 Sheetmils/8 shtTensile MD g/3 in 2793.50 2966.23 2880.07 2864.20 Stretch MD % 15.2315.90 15.30 14.87 Tensile CD g/3 in. 2492.66 2688.85 2723.01 2501.79Stretch CD % 9.58 9.52 9.50 8.97 Tensile GM g/3 in. 2638.12 2823.322799.58 2676.19 Tensile Dry Ratio 1.12 1.10 1.06 1.15 Unitless PerfTensile g/3 in. 624.56 682.48 647.34 704.59 Wet Tens Finch 717.31 762.97790.76 733.06 Cured CD g/3 in. Tensile Wet/Dry 0.29 0.28 0.29 0.29 CDUnitless SAT Capacity g/m² 481.81 499.80 499.30 494.75 SAT Rateg/s^(0.5) 0.20 0.26 0.26 0.28 SAT Times 44.07 31.98 29.71 26.31 BreakModulus MD 183.24 185.48 187.84 192.75 gms/% Break Modulus CD 259.48279.78 285.78 279.27 gms/% Break Modulus GM 218.00 227.76 231.67 231.94gms/% Modulus MD g/% 46.40 42.64 42.75 42.76 Stretch Modulus CD g/%64.30 63.57 64.38 61.86 Stretch Modulus GM g/% 54.59 52.04 52.43 51.39Stretch TEA MD mm- 2.67 2.94 2.72 2.62 g/mm² TEA CD mm- 1.55 1.62 1.631.41 g/mm² Roll Diameter In. 6.03 6.03 5.98 6.04 Roll Compression 4.596.63 6.41 6.90 Value % Roll Compression 5.75 5.63 5.60 5.63 in. BasisWeight Raw 1.97 1.98 2.00 1.98 Wtg. Sensory Softness 5.60 5.70 5.90 6.10

TABLE 8 Invention at Penetration of 55 mils (Percent Change fromBasesheet) Description Pattern A Pattern B Pattern C Pattern D BasisWeight −3.24 3.00 2.20 3.05 lb/3000 ft² Caliper 8 0.78 −5.69 −3.10 −3.14Sheetmils/8 sht Tensile MD g/3 in −5.45 −0.40 2.52 3.06 Stretch MD %−5.51 1.35 5.10 7.78 Tensile CD g/3 in. −15.33 8.66 7.50 15.02 StretchCD % 6.07 −5.44 −5.18 0.63 Tensile GM g/3 in. −10.48 4.19 5.00 9.18Tensile Dry Ratio 12.30 −10.00 −5.58 −14.23 Unitless Perf Tensile g/3in. Wet Tens Finch −14.58 9.15 5.84 12.71 Cured CD g/3 in. TensileWet/Dry −0.72 0.51 −1.84 −2.73 CD Unitless SAT Capacity g/m² SAT Rateg/s^(0.5) SAT Times Break Modulus MD 1.44 −2.68 −3.99 −6.70 gms/% BreakModulus CD −20.89 14.70 12.87 14.85 gms/% Break Modulus GM −10.40 6.384.78 4.67 gms/% Modulus MD g/% Stretch Modulus CD g/% Stretch Modulus GMg/% Stretch TEA MD mm- −10.50 1.62 9.00 12.21 g/mm²² TEA CD mm- −8.443.90 3.70 16.75 g/mm² Roll Diameter In. Roll Compression Value % RollCompression in. Basis Weight Raw −3.24 3.00 2.20 3.05 Wtg. SensorySoftness

The graphs presented in FIGS. 10 to 22 represent the outcome of Example2 compared directly to the current product.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

What is claimed is:
 1. A method of increasing the density of a rolledpaper product comprising: providing at least one paper web; embossingthe at least one web using an emboss pattern that covers at least about22% of the total surface area of the at least one web with an embosspattern of at least about 80% linear embossments to produce a denserweb, and; rolling the paper web to form a rolled paper product; whereinthe embossing causes an absorbency loss of no greater than 10%.
 2. Themethod of claim 1, wherein the emboss pattern includes at least about90% linear embossments.
 3. The method of claim 1, wherein the embosspattern includes at least about 95% linear embossments.
 4. The method ofclaim 1, wherein the emboss pattern includes 100% linear embossments. 5.The method of claim 1, wherein the depth of embossments is at leastabout 30 mils.
 6. The method of claim 1, wherein the depth ofembossments is at least about 45 mils.
 7. The method of claim 1, whereinthe depth of embossments is at least about 55 mils.
 8. The method ofclaim 1, wherein the paper product comprises two or more webs.
 9. Themethod of claim 7, wherein the embossing step both embosses and pliesthe webs.
 10. The method of claim 1, wherein the rolled paper producthas a caliper less than the caliper of the unembossed at least one webfrom which it is formed.
 11. The method of claim 1, wherein theabsorbency change is less than about 5%.